The New York-based hedge fund and Valeant Pharmaceuticals have joined forces in a hostile bid for Allergan Inc., the pharmaceutical company that makes Botox. Since striking its agreement with Valeant, Pershing Square has bought up some 9.7% of Allergan’s shares.

The deal, for cash and Valeant stock, is worth in excess of $45 billion.

Valeant has been seeking a deal for Allergan for a year, to no avail. The company said the merger would “create an unrivaled platform for growth and value creation in healthcare.”